Electrical controller



F. H. OBERSCHMIDT ELECTRICAL CONTROLLER Nov. 13, 1928. 1,691,735

Filed March 22, 1924 A TTORNE V L i 61* 1 L2 130 8 4%.. M

. 11 w? W /w 6 5 u M v 12, o- \J 16 -Patented Nov. 13, 1928.

'jmmcxno OF CLEVELAND, OHIO, ASSIGNOR TO THE comma-m- 109.00., 0] IILWAUIIE, WISCONSIN, A CORPORATION 01' WIBGONSDI'.

ELECTRICAL CONTROLLER.

Application fil ed larch 38, 1924. Serial Io. 700,985.

This invention relates to electrical controllers and more particularly to timing devices therefor.

An object of the invention is that of pro-- In the accompanying drawing, wherein are illustrated by way of example certain of the embodiments wh1ch the invention may as-v sume in practice Figure 1 is a diagrammatic view illustratmgi a proposed construction; while 2 and 3 are similar views illustrating m edconstructions.

Referrin to the drawing, and first to Fig. 1 thereof, e same illustrates byway of example an adaptation of the present principles to produce automatically and definitely timed stopping of an A. C. motor M, the latter to be supp ed from lines L L subject to control by an electroresponsive switch 5 in conjuncf tion with the means to be hereinafter described.

Said switch, which may comprise standard or conventional parts, is provided with a magnetic frame 6. having a pivoted, contact ca armature 7, the contact 8 of which is adapte in the closed or attracted position of said armatureto en ge fixed main and auxiliary contacts 9 an 10. Said switch is further provided with an energizing-coil 11 E to be connected across the supply lines in shunt to the motor, subject to control by a s rt a suita Is current limitin resistance 13 being included incircuit wit said coil.v Obviousl closure of contactor 8 serves to bridge the lixed contacts 9 and 10 thereby shunting push button or equivalent switch 12,

push button 12 and maintaining energization of coil 11 after opening of switch 12 in a well known manner.

An additional coil 14 is provided on frame 6 in a relation to derive energy. inductively from coil 11 durin energization of the latter. A heating coll or uivalent device 15 is arranged in circuit wit the coil 14 to be heated by current flowing in their joint circuit. A suitable thermo-res onsive contacting device 16 subjected to'i uence of heater 15 is arranged-to control continuity of a circuit shunting the coil 11. p Upon closure of switch 12 the energizing circuit of coil 11 is completed whereupon switch 5 responds and com letes the motor circuit. Also as aresult o energization of coil 11 induced current flows in the circuit of coil 14 and heater 15. The thermo-responsive contactor 16 being subjected .to the resultant rise in' tem erature is adapted, subject to a definite time element, to close the circuit shuntin the coil 11 whereupon switch 5 dro s out an deenergizes the motor M and opiemng the maintaining circuit of coil 11. A so as a result of deenergization of coil 11, coil 14 and heater 15 are also deenergiz'ed whereupon element 16 is adapted to rename its normal relation interrup'tingthe shunt around coil 11 thereby resetting the elements of the controller for subsequent starting of motor M in the manner aforedescribed.

The construction shown in Fig. 2 is in eneral quite similar to that described. ow-- ever, 1n this instance the coil 14 of switch 5 is omitted or consolidated with coil 11 to produce the structure depicted at 11, thereby obviating the necessit of providing separate coils upon the switc frame. The thermoresponsive element 16 is moreover shown in the form of a thermostatic resistance grid adapted upon passage of current therethrough to become heated and conseqfily deformed to close circuit as aforedescrl Also the push button 12 is of the latched-in type thus obviating the necessity of providing: maintaining contact on switch 5. 96 practice the switch 12 may be prefer- I said switch'when closed. Said latch 17 is provided with a contact portion or element arranged in the; energizing circuit of 0011 11 as shown, whereb upon engagement ,of mid contact portion y the element 16 the coil 11 is shunted and switch 5 permitted to open; However, under these conditions the element 16, or the major portion thereof is maintained in circuit and hence continues to undergo deformation for ultimate tripping of latch 17 whereupon switch 12 is adapted to open, deenergizlng element 16 to permit cooling of the latter and thus affect resetting of the controller to provide for restarting of the motor upon depression of switch 12. The latch'17 may be of conductive material adapted when in latching relation to contact with the bridgin element of switch 12. However, it is pre erred to insulate said members as shown to thereby insure that circuit interruption occur at the switch contacts rather than between the switch contactor and the latch. A suitable stop or abutment, such as indicated at 19, is preterably provided to limit the movement of latch 17 under the action of its biasing means.

A variable resistance device 18 may be arranged to be in circuit with the element 16 for varying the time element of the latter. Also plural taps may be provided upon the coil 11, as indicated, for an analogous purpose, whereas an adjustable screw is ref- .erably provided upon the latch 17 for a ording further calibration.

The construction illustrated in Fig. 3 difffers from that of Fig. 2 in that the element 16 is arranged permanently in shunt to .coil 11 whereby the energy applied to the former is maintained proportional to that of the latter, the proportionality however being variable by adjustment of resistance device 18 as in Fig. 2. Also said element 16 is adapted to act merely mechanically for tripping latch 17 subject to a definite'pred'eterminable time element for accurately timed stopping of motor M, the controller also being automatically reset. The abutment 19 serves to limit the degree of counterclockwise movement of latch 17, as noted in connection with latch 17, Fig. 2'.

i In each of the aforedescribed constructions it is to be observed that the value of the heat energy applied to the thermo-responsive element is substantially independent of the power consumption of the motor but is maintained proportional to the energy con sumption of the switchclosing coil, which latter value is substantially a. constant, "whereby extreme accuracy and uniformity of the time element of response, subject to 5 accurate calibration, is provided.

1. In a controller for electric motors and i the like, the combination with control means for the motor and thermo-responsive timing inductive means for said control means, of means to subject said thermo-responsive means to thermic influence of a value substantially independent of the value of energy consumed bythe controlled motor.

2. In a controller for electric motors and the like, the combination with electro-magnetically operable control means for the-motor and thermo-responsive timing means for said control means, of inductive means to subject said thermo-res nsive means to thermic influence of a. va ue proportional to the value of energization of said electro-magnetically operable means but substantially independent of the value of energy consumed by said motor.

3. In a controller for electric motors and the like, the combination with electro-magnetically operable control means for the mo tor and thermo-responsive timing means for said control means, of means to be inductively energized by flux of said electro-magnetically operable control means for subjectin said thermo-responsive means to thermic uence of a value substantially independent of the value of energy consumed by the motor.

4. In a controller for electric motors and the like, the combination with a switch and electro-magnetic operating means therefor comprising a field= member halving an energizing coil, of thermo-responsive means for controlling energization of said coil and means associated with said switch operating means to be inductively ener zed by flux traversing said field member r subjecting said thermo-responsive means to thermic influence of a value substantiall independent of the value of energy consumed 5. In a controller for" electric motors and the like, the combination with a switch and by the motor.

electro-magnetic operating means therefor comprisin a field member having an energizing coi of thermo-responsive means for shunting said coil, the latter having associated means to be traversed by inductively created current for subjecting said thermoresponsive means to thermic influence.

6. In a controller for electric motors and the like,'the combination with a switch and electro-magnetic operating means therefor comprising a field member havin an energizing coil, a switch to control continuity of the circuit of said coil, means providm for definitely timed deenergization of sai coil, comprising a thermo-responsive contactor operable sequentially to shunt said coil and to cause openin of said switch, and inductive means to su ject said thermo-responsive means to a definite value of thermic influence.

successive values of response of said grid the same is adapted to shunt said coil and 10 thereafter to trip said switch for resetting the controller.

In witness whereof, I have hereunto subscribed my name.

FREDERICK H. OBERSCHMIDT.

CERTIFICATE OF CORRECTION.

Patent No. 1,691,735,

Granted November 13, 1928, to

FREDERICK n. OBERSGHMIDT.

It is hereby certified that-"errorappears in the printed specification of the above numbered patent requiring corre strike'out the word "inductive" ction as follows: Page 2, line 71-, claim 1, and insert the same after the word- "of" in the sameklinefand that the said Letters Patent should be read with this correction there n that the, same may conform to the record of the case in the'latent Office.-

' Signed and sealed this 8th day of January; A. D. 1929.

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'J. Moore, Acting Commissioner of Patents. 

